US20090059838A1 - Methods and apparatuses for efficiently using radio resources in wireless communication system based on relay station (RS) - Google Patents

Abstract

Methods and apparatuses for efficiently using radio resources in a wireless communication system based on a relay station are provided. An operating method of a relay station (RS) for efficiently using radio resources in a wireless communication system based on the RS. The method includes setting a call with a sending terminal; checking whether a receiving terminal of the sending terminal travels in the same RS cell, in a different RS cell of the same base station (BS) cell, or in a different cell of a neighbor BS; and checking a destination address of a data and relaying the data to the receiving terminal according to a result of the checking.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY
• This application claims priority under 35 U.S.C. § 119 (a) to a Korean patent application filed in the Korean Intellectual Property Office on Sep. 3, 2007 and assigned Serial No. 2007-88973, the entire disclosure of which is hereby incorporated by reference.
TECHNICAL FIELD OF THE INVENTION
• The present invention relates generally to a wireless communication system based on a relay station. More particularly, the present invention relates to methods and apparatuses for efficiently using radio resources in the wireless communication system based on the relay station.
BACKGROUND OF THE INVENTION
• Researches are conducted on a multi-hop relay transmission technique which is an efficient data delivery scheme in an ad-hoc system. Recently, the multi-hop transmission scheme is attracting much attention as the technique to extend a service coverage of the cell at a low cost and to provide a high-speed data transmission to users in the wireless communication system. For example, the Institute of Electrical and Electronics Engineers (IEEE) 802.16j standard group is standardizing a Mobile Multihop Relay (MMR) technology.
• A multihop transmission using a relay station (RS) in a wireless communication system is illustrated by referring toFIGS. 1,2 and3.
• FIG. 1 depicts a conventional communication scenario between mobile stations (MSs) in the same RS service coverage in the wireless communication system. For communications, the MS111 and the MS112 in the same service coverage of the RS110 operate in the wireless communication system as follows.
• Provided that the MS111 sends data to the MS112, thefirst transmission113 is made from the MS111 to the RS110 and thesecond transmission114 is made from the RS110 to a base station (BS)100. Thethird transmission115 is made from the BS100 to the RS110. Finally, thefourth transmission116 is made from the RS110 to the MS112. For the data delivery from the MS111 to the MS112, radio resources are required for the data transmissions per interval (MS111-RS110, RS110-BS100, BS100-RS110, and RS110-MS112).
• FIG. 2 depicts a conventional communication scenario between MSs in different RS service coverage within the same cell in a wireless communication system. The communications between the MSs in the same cell of the wireless communication system is performed as follows. Herein, the communication scenario between the MSs in the same cell considers that the MSs communicate via different RSs respectively within the same cell.
• Provided that the MS211 sends data to the MS221, the MS211 makes thefirst transmission212 to an RS210 and the RS210 makes thesecond transmission213 to a BS200. Next, the BS200 makes thethird transmission214 to an RS220 and the RS220 makes thefourth transmission215 to the MS221. As inFIG. 1, the data transmission from the MS211 to the MS221 requires radio resources per interval (MS211-RS210, RS210-BS200, BS200-RS220, and RS220-MS221).
• FIG. 3 depicts a conventional communication scenario between MSs in neighbor cells of a wireless communication system. The communications between theMS325 and theMS341 in the neighbor cells of the wireless communication system is performed as follows.
• AnRS320 belongs to a coverage of aBS300, and anRS340 belongs to a coverage of aBS310. To transmit data from theMS325 to the MS341, thefirst transmission321 is made from the MS325 to the RS320 and thesecond transmission322 is made from the RS320 to the BS300. The BS300 sends the data to the BS310 over a backbone network. Next, the BS310 makes thethird transmission323 to the RS340 and the RS340 makes thefourth transmission324 to the MS341. Hence, as inFIGS. 1 and 2, the data transmission from the MS325 to the MS341 requires radio resources per interval (MS325-RS320, RS320-BS300, BS310-RS340, and RS340-MS341) and a wired resource between the BS300 and the BS310 over the backbone network.
• Utilization of the radio resource for the relay transmission is explained by referring toFIGS. 4 and 5 showing an Orthogonal Frequency Division Multiplexing (OFDM) frame structure.
• FIG. 4 depicts a conventional half-duplex OFDM frame structure.
• An uplink and a downlink inFIG. 4 are separated based on a transmission time. The DownLink (DL) transmission starts with one preamble symbol, a Frame Control Header (FCH), DL-MAP, UL-MAP, and data symbols in order. Receive/transmit Transition Gap (RTG) and Transmit/receive Transition Gap (TTG), which are guard times to distinguish UL and DL transmission times, are inserted between frames and between the downlink and the uplink at the end respectively.
• The preamble symbol is used for network synchronization and cell search. The FCH symbol is used to carry frame constitution information. The DL MAP symbols include Information Element (IE) and constitution information of bursts transmitted in the downlink, and the UL MAP symbols include IE and constitution information of bursts transmitted in the uplink.
• For the relay transmission, the frame can be divided into aBS frame400 and anRS frame410 based on subcarriers. In various implementations, the frame can be divided based on the transmission time. Herein, theBS frame400 is subdivided into a DownLink (DL)subframe401 and an UpLink (UL) subframe402. TheDL subframe401 is subdivided into anaccess zone403 and arelay zone404. Theaccess zone403 is used to transmit data from the BS to the MS, and therelay zone404 is used to transmit data from the BS to the RS. Likewise, the UL subframe402 is subdivided into anaccess zone405 and arelay zone406. Theaccess zone405 is used to transmit data from the MS to the BS, and therelay zone406 is used to receive data at the BS from the RS. TheRS frame410 is divided to aDL subframe411 and aUL subframe412. TheDL subframe411 is subdivided into anaccess zone413 and arelay zone414. Theaccess zone413 is used to transmit data from RS to the MS, and therelay zone414 is used to receive data at the RS from the BS. Likewise, theUL subframe412 is subdivided into anaccess zone415 and arelay zone416. Theaccess zone415 is used to transmit data from the MS to the RS, and therelay zone416 is used to transmit data from RS to the BS.
• For the relay transmission ofFIGS. 1,2 and3, the first data transmission is performed to theaccess zone415 of theUL subframe412 through the UL MAP information of theDL subframe411. The second data transmission is performed to therelay zone406 of the UL subframe402 through the relay UL MAP information of theDL subframe401. The third data transmission is conducted to therelay zone404 of theDL subframe401 through the relay DL MAP information of theDL subframe401. The fourth data transmission is conducted to theaccess zone413 of theDL subframe411 through the DL MAP information of theDL subframe411.
• FIG. 5 depicts a conventional full-duplex OFDM frame structure.
• The preamble, the FCH, the DL MAP, and the UL MAP of the frame ofFIG. 5 are substantially the same as inFIG. 4 and are thus not further explained.
• For the full-duplex transmission, aBS frame500 that is used to transmit data from the BS to the RS or the MS and data from the RS or the MS to the BS, afirst RS frame510 that is used to receive data from the BS to the RS and to receive data from the MS to the RS, and asecond RS frame520 that is used to transmit data from the RS to the MS and to transmit data from the RS to the BS are allocated to different frequency bands.
• For the relay transmission ofFIGS. 1,2 and3, the first data transmission is conducted into the access zone of theUL subframe512 of thefirst RS frame510. For the first data transmission, UL MAP information of theDL subframe521 of thesecond RS frame520 is used. Next, the second data transmission is performed into the relay zone of theUL subframe522 of thesecond RS frame520. For the second data transmission, UL MAP information of the DL subframe501 of theBS frame500 is used. The third data transmission is conducted into the relay/access zone of theDL subframe502 of theBS frame500. For the third data transmission, DL MAP information of the DL subframe501 of theBS frame500 is used. Next, the fourth data transmission is made into the access zone of theDL subframe521 of thesecond RS frame520. For the fourth data transmission, DL MAP information of theDL subframe521 of thesecond RS frame520 is used.
• As discussed above, for the relay transmission in the wireless communication system based on the relay station, separate resources are allocated to the paths respectively. As a result, as the number of the relay hops increases, more resources are required.
SUMMARY OF THE INVENTION
• To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to address at least the above mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide methods and apparatuses for efficiently using radio resources in a wireless communication network based on a relay station.
• The above aspects are achieved by providing an operating method of a relay station (RS) for efficiently using radio resources in a wireless communication system based on the RS. The method includes setting a call with a sending terminal; checking whether a receiving terminal of the sending terminal travels in the same RS cell, in a different RS cell of the same base station (BS) cell, or in a different cell of a neighbor BS; and checking a destination address of data and relaying the data to the receiving terminal according to a result of the checking.
• According to one aspect of the present invention, an operating method of a BS for efficiently using radio resources in a wireless communication system based on a RS, includes receiving call setup information from an RS; and allocating a resource for connection between RSs.
• According to another aspect of the present invention, an apparatus for a RS for efficiently using radio resources in a wireless communication system based on the RS, includes a call setter for setting a call with a sending terminal; a receiving terminal checker for checking whether a receiving terminal of the sending terminal travels in the same RS cell, in a different RS cell of the same base station (BS) cell, or in a different cell of a neighbor BS; and a controller for checking a destination address of data and relaying the data to the receiving terminal according to a result of the checking.
• According to yet another aspect of the present invention, an apparatus for a BS for efficiently using radio resources in a wireless communication system based on a RS, includes a controller for receiving call setup information from an RS; and a resource allocator for allocating a resource for connection between RSs.
• Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
• Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior uses, as well as future uses of such defined words and phrases.
BRIEF DESCRIPTION OF THE DRAWINGS
• For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:
• FIG. 1 illustrates a conventional communication scenario between mobile stations (MSs) in the same relay station (RS) service coverage in a wireless communication system;
• FIG. 2 illustrates a conventional communication scenario between MSs in different RS service coverages within the same cell in a wireless communication system;
• FIG. 3 illustrates a conventional communication scenario between MSs in neighbor cells of a wireless communication system;
• FIG. 4 illustrates a conventional half-duplex OFDM frame structure;
• FIG. 5 illustrates a conventional full-duplex OFDM frame structure;
• FIG. 6 illustrates a communication scenario between MSs in the same RS service coverage in a wireless communication system according to one exemplary embodiment of the present invention;
• FIG. 7 illustrates a half-duplex frame structure ofFIG. 6;
• FIG. 8 illustrates a full-duplex frame structure ofFIG. 6;
• FIG. 9 illustrates a communication scenario between MSs in different RS service coverages within the same cell in a wireless communication system according to another exemplary embodiment of the present invention;
• FIG. 10 illustrates a half-duplex frame structure ofFIG. 9;
• FIGS. 11A and 11B illustrate a full-duplex frame structure ofFIG. 9;
• FIG. 12 illustrates a communication scenario between MSs in neighbor cells of a wireless communication system according to yet another exemplary embodiment of the present invention;
• FIG. 13 illustrates an MS-RS service flow setting method in a broadband wireless communication system;
• FIG. 14 illustrates an RS-MS service flow setting method in the broadband wireless communication system;
• FIG. 15 illustrates a method for efficiently using radio resources in the communication scenario between the MSs in the same RS service coverage according to one exemplary embodiment of the present invention;
• FIG. 16 illustrates a method for efficiently using radio resources in the communication scenario between the MSs in the different RS service coverages within the same cell according to another exemplary embodiment of the present invention;
• FIG. 17 illustrates a method for efficiently using radio resources in the communication scenario between the MSs in the neighbor cells according to yet another exemplary embodiment of the present invention;
• FIG. 18 illustrates an RS for efficiently using radio resources in the communication scenario between the MSs in the neighbor cells according to an exemplary embodiment of the present invention; and
• FIG. 19 illustrates a BS for efficiently using radio resources in the communication scenario between the MSs in the neighbor cells according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
• FIGS. 6 through 19, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged wireless communication system.
• Exemplary embodiments of the present invention provide methods and apparatuses for efficiently using radio resources in a wireless communication system based on a relay station.
• FIG. 6 illustrates a communication scenario (hereafter, referred to as a first scenario) between mobile stations (MSs) in the same relay station (RS) service coverage of a wireless communication system according to one exemplary embodiment of the present invention.
• Provided that anMS611 transmits data to anMS612 in the same RS service coverage, thefirst transmission613 is made from theMS611 to anRS610 and thesecond transmission614 is made from theRS610 to theMS612. Compared to the conventional method ofFIG. 1, the communications of the first scenario require radio resources only for the MS611-RS610 interval and the RS610-MS612 interval. The method of the present invention is more advantageous than the conventional method in terms of the radio resource efficiency.
• The basic frame structure is now explained by referring toFIG. 7 showing a half-duplex frame structure andFIG. 8 showing a full-duplex frame structure.
• A base station (BS)frame700 for communications between the BS and the RS and communications between the BS and the MS includes a DownLink (DL)subframe701 and an UpLink (UL) subframe702. TheDL subframe701 carries data from the BS to the MS (BS→MS: access zone) and data from the BS to the RS (BS→RS: relay zone). The access zone and the relay zone of theDL subframe701 are separated based on the time. The UL subframe702 carries data from the MS to the BS (MS→BS: access zone) and data from the RS to the BS (RS→BS: relay zone).
• Likewise, anRS frame710 for communications between the RS and the MS and communications between the RS and the BS includes aDL subframe711 and theUL subframe712. TheDL subframe711 carries data from the RS to the MS (RS→MS: access zone) and receives data from the BS to the RS (BS→RS: relay zone). The access zone and the relay zone of theDL subframe711 are separated based on the time. TheUL subframe712 receives data from the MS to the RS (MS→RS: access zone) and carries data from the RS to the BS (RS→BS: relay zone).
• According to the first scenario, the first transmission is made over the access zone (MS→RS) in theUL subframe712 of theRS frame710. The RS identifies a receiving terminal in its service coverage and makes the second transmission in the access zone (RS→MS) of theDL subframe711 of theRS frame710. That is, theBS frame700 is not used because the communications between the RS and the BS or between the MS and the BS is unnecessary in the first scenario.
• InFIG. 8, aBS frame800 for communications between BS and RS and communications between BS and MS includes aDL subframe801 and aUL subframe802. TheDL subframe801 carries data from the BS to the MS (BS→MS: access zone) and data from the BS to the RS (BS→RS: relay zone). In the full-duplex communication, the access zone and the relay zone of theDL subframe801 are not separated based on the time. TheUL subframe802 carries data from the MS to the BS (MS→BS: access zone) and data from the RS to the BS (RS→BS: relay zone). In the full-duplex communication, the access zone and the relay zone of theUL subframe802 are not separated based on the time.
• The RS frame for communications between the RS and the MS and communications between the RS and the BS includes anRS frame810 of a first antenna for the reception and anRS frame820 of a second antenna for the transmission. In theRS frame810 of the first antenna, aDL subframe811 carries data from the BS to the RS and aUL subframe812 carries data from the MS to the RS. In theRS frame820 of the second antenna, aDL subframe821 carries data from the RS to the MS and aUL subframe822 carries data from the RS to the BS. Accordingly, as the RS receives data from the BS over theDL subframe811 of theRS frame810 of the first antenna, the RS transmits data to the MS over theDL subframe821 of thesecond RS frame820 at the same time. As the RS receives data from the MS over theUL subframe812 of theRS frame810 of the first antenna, the RS transmits data to the BS over theUL subframe822 of theRS frame820 of the second antenna at the same time. Thus, the full-duplex communications are made.
• According to the first scenario, the first transmission is made in the access zone (MS→RS) of theUL subframe812 of theRS frame810. The RS identifies a receiving terminal in its service coverage and makes the second transmission in the access zone (RS→MS) of theDL subframe821 of theRS frame820. That is, theBS frame800 is not used because the communications between the RS and the BS or between the MS and the BS is unnecessary in the first scenario.
• In the call setup, theRS610 confirms a MAC address of theMS612 and determines whether to perform the call setup procedure to theBS600. Next, theRS610 receives thedata613 from theMS611 over the UL access zone and relays thedata614 to theMS612 over the DL access zone of the next frame. Compared to the conventional method, the resources of the UL and DL relay zones can be saved. A signaling process for efficiently using the radio resources according to the first scenario is described in detail by referring toFIG. 15.
• FIG. 15 illustrates a method for efficiently using radio resources in the communication scenario between the MSs in the same RS service coverage according one exemplary embodiment of the present invention. Herein, a call setup procedure, a data communication procedure, and a call termination procedure are described individually.
• TheMS611 performs the call setup procedure for the data communications with theMS612 as follows.
• The MS611 (MS₁) sends a request message for the call setup to theRS610 instep1500. TheRS610 sends a response message to the MS611 (MS₁) in reply to the request message in step1502. By exchanging those messages, the a Connection IDentifier (CID) can be allocated for the data communications between theMS611 and theRS610 instep1504. For example, in the broadband wireless communication system, the MS may set the uplink call by exchanging DSA-REQ and DSA-RSP messages to generate a service flow to the BS. Referring toFIG. 13, in the broadband wireless communication system, theMS611 sends a DSA-REQ message1300 to theRS610 andRS610 sends a DSA-RVD message1302 or a DSA-RSP message1304 to theMS611 to indicate the approval or the disapproval. Next, theMS611 sends a DSA-ACK message1306 to theRS610.
• Referring back toFIG. 15, theRS610 identifies an MS with which theMS611 intends to communicate data instep1506. Herein, it is assumed that the MS612 (MS₂) that is to communicate with the MS611 (MS₁) exists within the coverage of theRS610. Instep1508, theRS610 sends a message for call setup information and authentication/charging to theBS600, rather than for the call setup procedure to allocate the CID as shown inFIG. 13. That is, a transport CID is not allocated for the traffic data delivery between theRS610 and theBS600, whereas only the notification of the call setup is performed.
• After exchanging control information of the call setup with theBS600 in step1510, theRS610 sends a call setup request message to the MS612 (MS₂) instep1512. The MS612 (MS₂) sends a response message of the request message to theRS610 in step1514. By exchanging the call setup related messages as above, the CID for the data communications between theRS610 and MS612 (MS₂) is allocated instep1516. Referring toFIG. 14, in the broadband wireless communication system, theRS610 exchanges a DSA-REQ message1400, a DSA-RSP message1402, and a DSA-ACK message1404 with theMS612 to generate the service flow and thus sets the downlink call.
• After the call setup, the MS611 (MS₁) and the MS612 (MS₂) request a bandwidth for the data communications and are assigned the bandwidth.
• Referring back toFIG. 15, the MS611 (MS₁) transmits data packets to theRS610 using the allocated bandwidth instep1518. TheRS610 receives the data packets, decodes the corresponding packets, and then confirms the destination MAC address instep1520. When the destination MAC address is the MAC address of the MS612 (MS₂) in the coverage of theRS610, theRS610 relays the corresponding data packets directly to the MS612 (MS₂) instep1522, not to theBS600. TheRS610 should store MAC addresses of MSs belonging to theRS610. In doing so, using the CID allocated per MS, the half-duplex communications and the full-duplex communications both can be executed using the resources of the UL access zone and the DL access zone. In the centralized scheduling, theBS600 allocates the resources and transmits the MAP information. In the distributed scheduling, theRS610 allocates the resources and transmits the MAP information.
• After the call termination between the MS611 (MS₁) and the MS612 (MS₂), theRS610 needs to send information relating to the termination of the corresponding connection and the charging information to theBS600. For example, the MS611 (MS₁) sends a call termination message to theRS610 instep1524. In various implementations, the MS612 (MS₂) may send the call termination message to theRS610 instep1526.
• Instep1528, theRS610 sends the call termination information/charging information message to theBS600. Instep1530, theBS600 sends a call_termination_info_ack message to theRS610 in response.
• FIG. 9 illustrates a communication scenario (hereafter, referred to as a second scenario) between MSs in different RS service coverages within the same cell of a wireless communication system according another exemplary embodiment of the present invention.
• Provided that an MS911 (MS₁) transmits data to an MS921 (MS₂), thefirst transmission912 is made from the MS911 (MS₁) to an RS910 (RS₁), thesecond transmission913 is made from the RS910 (RS₁) to an RS920 (RS₂), and thethird transmission914 is made from the RS920 (RS₂) to the MS921 (MS₂). Compared to the conventional method ofFIG. 2, the communications according to the suggested scenario requires the radio resources only for the MS911-RS910 interval, the RS910-RS920 interval, and the RS920-MS921 interval. In conclusion, the present invention is advantageous more than the conventional method in terms of the radio resource efficiency.
• A basic frame structure for the second scenario is described by referring toFIG. 10 showing the half-duplex frame structure andFIG. 11 showing the full-duplex frame structure.
• The half-duplex frame ofFIG. 10 is similar to that ofFIG. 7. Yet, since the second scenario assumes that the MSs exist in the different RS service coverage within the same cell, resource is required for communications between RSs while no resource is required for communications between the RS and the BS. Accordingly, the frame ofFIG. 10 additionally includes the resources for the communications between the RSs, compared to the half-duplex frame ofFIG. 7.
• For example, according to the second scenario, the first transmission is made over the access zone (MS→RS) of theUL subframe1012 of thefirst RS frame1010. The RS identifies a receiving MS in the different RS service coverage within the same cell, and the BS allocates resource for the communications between the first RS910 (RS₁) and the second RS920 (RS₂). TheBS900 informs thefirst RS910 and thesecond RS920 of the allocated resource position through Direct Tx/Rx MAP information of theBS frame1000. Herein, the resource regions for the second transmission between thefirst RS910 and thesecond RS920 are the relay zone of theUL subframe1012 of thefirst RS frame1010 and the relay zone of theUL subframe1022 of thesecond RS frame1020. Since the frame zone between the RS and the BS is not used, the frame zone between the RS and the BS is allocated and used as the second transmission zone. In doing so, additional TTG is required so that thesecond RS920 needs to receive data in the time resource region of the transmission of thefirst RS910. Finally, the third transmission is made over the access zone (RS→MS) of theDL subframe1021 of thesecond RS frame1020.
• The full-duplex frame ofFIG. 11 is similar to that ofFIG. 8. Yet, since the second scenario assumes that the MSs exist in the different RS service coverages within the same cell, resource is required for communications between RSs while no resource is required for communications between the RS and the BS. Accordingly, the frame ofFIG. 11 additionally includes the resources for the communications between the RSs, compared to the full-duplex frame ofFIG. 8.
• For example, according to the second scenario, the first transmission is made in the access zone (MS→RS) of theUL subframe1122 of the frame1120 of the first antenna for the first RS. Next, the RS identifies a receiving MS in the different RS service coverage within the same cell, and the BS allocates the resource for the communications between thefirst RS910 and thesecond RS920. TheBS900 informs the first RS910 (RS₁) and the second RS920 (RS₂) of the allocated resource position through Direct Tx/Rx MAP information of theBS frame1100. Herein, the resource regions for the second transmission between thefirst RS910 and thesecond RS920 are the relay zone of the UL subframe1142 of thesecond antenna frame1140 for thefirst RS910 and the relay zone of theUL subframe1132 of the first antenna frame1130 for thesecond RS920. That is, when the second transmission is made in the relay zone of the UL frame1142, the second transmission is received in the relay zone of theUL subframe1132. Since the full-duplex scheme concurrently performs the transmission in the UL subframe1142 and the reception in theUL subframe1132 for the second transmission, additional relay TTG as in the half-duplex communications is unnecessary. In various implementations, the resource region for receiving the second transmission may use the relay zone of theDL subframe1131 of the first antenna frame1130 for thesecond RS920.
• Finally, the third transmission is made over the access zone (RS→MS) of theDL subframe1151 of thesecond antenna frame1150 for thesecond RS920.
• The communication resource in each link can use the access zone resource in thefirst transmission912 and thethird transmission914. In the centralized scheduling, theBS900 handles the resource allocation. In the distributed scheduling, theRSs910 and920 inform of the resource allocation using the MAP information. Herein, in thesecond transmission913 between theRS910 and theRS920, theBS900 allocates the resource, defines and sends the Direct Tx/Rx MAP information.FIG. 10 depicts the frame structure of the full-duplex scheme, and the communication resource between the RSs utilizes the resource of the relay zone. Since thesecond RS920 needs to receive data in the time resource zone where thefirst RS910 transmits data, additional relay TTG is required.FIG. 11 depicts the frame structure of the full-duplex scheme, and theBS900 allocates and informs of the communication resource between the RSs using the Direct Tx/Rx MAP information. In the full-duplex communications, theRSs910 and920 perform the reception and the transmission at the same time. In doing so, since additional relay TTG as in the half-duplex communications is unnecessary, the present invention is very advantageous.
• FIG. 16 illustrates a method for efficiently using radio resources in the communication scenario between the MSs in the different RS service coverage within the same cell according another exemplary embodiment of the present invention. The call setup procedure, the data communication procedure, and the call termination procedure are described separately.
• To communicate data with the MS921 (MS₂), the MS911 (MS₁) performs the call setup procedure as below. Instep1600, the MS911 (MS₁) sends a call setup request message to the RS910 (RS₁).
• The RS910 (RS₁) sends a response message to the MS911 (MS₁) in response in step1602. By exchanging those messages, a CID for the data communications between the MS911 (MS₁) and the RS910 (RS₁) can be allocated instep1604.FIG. 13 is the flowchart of the call setup in the broadband wireless communication system.
• Instep1606, the RS910 (RS₁) identifies the MS with which the MS911 (MS₁) intends to communicate. It is assumed that the MS921 (MS₂) that is to communicate with the MS911 (MS₁) exists within the coverage of the RS920 (RS₂). Instep1608, the RS910 (RS₁) sends a message for the call setup information and the authentication/charging, rather than perform the call setup procedure to allocate the CID as shown inFIG. 15. That is, no transport CID is allocated between the RS910 (RS₁) and theBS900, whereas only the notification of the call setup is performed.
• Next, for the direction communications between the RS910 (RS₁) and the RS920 (RS₂), a new CID needs to be allocated. TheBS900 allocates this resource. For instance, the RS910 (RS₁) sends a DSA-REQ message to theBS900, and theBS900 responds with the DSA-RSP message indicative of the approval or the disapproval. The RS910 (RS₁) informs that the requested call concerns the connection to the RS920 (RS₂), not the connection to theBS900.
• In step1612, the RS920 (RS₂) sends a call setup request message to the MS921 (MS₂). The MS921 (MS₂) sends a response message of the request message in step1614. By exchanging the call setup related messages, the CID for the data communications between the RS920 (RS₂) and the RS910 (RS₁) is allocated in step1616.
• After the call setup, the MS911 (MS₁) and the MS921 (MS₂) request and get the bandwidth for the data communication.
• Instep1618, the MS911 (MS₁) transmits data packets to the RS910 (RS₁) using the allocated bandwidth. After receiving the data packets, the RS910 (RS₁) decodes the corresponding packets and checks a destination MAC address instep1620. When the destination MAC address is a MAC address of the MS921 (MS₂) existing in the coverage of the neighbor RS920 (RS₂), the RS910 (RS₁) relays the corresponding data packets directly to the RS920 (RS₂), rather than to theBS900. For doing so, the RS910 (RS₁) should know MAC addresses of MSs belonging to the neighbor RS920 (RS₂). To this end, a routing table is required. Information in the routing table includes field values relating to neighbor RS IDs, MAC addresses of MSs belonging to the corresponding RS, and so on.
• After the call termination between the MS911 (MS₁) and the MS921 (MS₂), when the corresponding connection is terminated instep1626, the RS910 (RS₁) needs to transmit information relating to the call termination and the charging instep1628. The RS910 (RS₁) transmits the call termination information/charging information message to theBS900 instep1628. The MS921 (MS₂) transmits the call termination information to the RS920 (RS₂) instep1630. The RS920 (RS₂) transmits the call termination/charging information to theBS900 instep1632. In response, theBS900 sends a call_termination_info_ack message to the RS910 (RS₁) and to the RS920 (RS₂) (in steps not shown inFIG. 16).
• FIG. 12 illustrates a communication scenario between MSs in neighbor cells of a wireless communication system according to yet another exemplary embodiment of the present invention.
• Provided that an MS1221 (MS₁) transmits data to an MS1231 (MS₂), thefirst transmission1222 is made from the MS1221 (MS₁) to an RS1220 (RS₁), thesecond transmission1223 is made from the RS1220 (RS₁) to an RS1230 (RS₂), and thethird transmission1224 is conducted from the RS1230 (RS₂) to the MS1231 (MS₂). Compared to the conventional method ofFIG. 3, the communications according to the suggested scenario requires radio resources only for the MS1221-RS1220 interval, the RS1220-RS1230 interval, and the RS1230-MS1231 interval. Hence, the present invention is advantageous more than the conventional method in terms of the radio resource efficiency.
• The communication resource operation in each link in thefirst transmission1222 and thethird transmission1224 are substantially the same as inFIG. 2. Yet in thesecond transmission1223, the communication resource between the RSs should be designated. A BS1200 (BS₁) or a BS1210 (BS₂) can allocate the communication resource. Herein, the BS of the transmitting RS allocates the resource. In more detail, the BS1200 (BS₁) allocates the communication resource between the RS1220 (RS₁) and the RS1230 (RS₂) and informs the BS1210 (BS₂) of the resource allocation. Based on the shared RS resource allocation information, each BS informs the RS1220 (RS₁) and the RS1230 (RS₂) of the transmit resource position and the receive resource position of the second data transmission using the Direct Tx/Rx MAP message. The frame structure is the same as in the second scenario. Since the full-duplex communications requires no additional relay TTG, it is far more efficient.
• FIG. 17 illustrates a method for efficiently using radio resources in the communication scenario between the MSs in the neighbor cells according to yet another exemplary embodiment of the present invention. The call setup procedure, the data communication procedure, and the call termination procedure are separately explained.
• To communicate data with the MS1231 (MS₂), the MS1221 (MS₁) performs the call setup procedure as below.
• The MS1221 (MS₁) sends a call setup request message to the RS1220 (RS₁) instep1700. The RS1220 (RS₁) sends a response message of the request message to the MS1221 (MS₁) instep1702. By exchanging those messages, a CID for the data communications between the MS1221 (MS₁) and the RS1220 (RS₁) can be allocated instep1704.
• In step1706, the RS1220 (RS₁) identifies an MS with which the MS1221 (MS₁) intends to communicate data. It is assumed that the MS1231 (MS₂) that is to communicate with the MS1221 (MS₁) exists within the coverage of the RS1230 (RS₂). The RS1220 (RS₁) sends a message for the call setup information and the authentication/charging to the BS1200 (BS₁) instep1708, rather than performs the call setup procedure to allocate the CID as shown inFIG. 13 orFIG. 14. In other words, the transport CID is not allocated between the RS1220 (RS₁) and the BS1200 (BS₁), and only the notification of the call setup is performed.
• Next, the BS1200 (BS₁) transmits the call setup information of the MS1221 (MS₁) and the MS1231 (MS₂) to the BS1210 (BS₂) over the backbone network instep1710. In doing so, it is necessary to determine whether the BS1200 (BS₁) or the BS1210 (BS₂) allocates the communication resource between the RS1220 (RS₁) and the RS1230 (RS₂). In this exemplary embodiment, the BS of the RS which transmits data allocates the resource. Thus, the RS1220 (RS₁) sends a DSA-REQ message to the BS1200 (BS₁), and the BS1200 (BS₁) responds with a DSA-RSP message indicative of the approval or the disapproval, which are not illustrated inFIG. 17. The RS1220 (RS₁) informs that the requested call pertains to the connection to the RS1230 (RS₂), rather than the connection to the BS.
• Next, the RS1230 (RS₂) sends a call setup request message to the MS1231 (MS₂) instep1714. The MS1231 (MS₂) sends a response message of the request message to the RS1230 (RS₂) in step1716. By exchanging the call setup related messages, a CID for the data communications between the RS1230 (RS₂) and the MS1231 (MS₂) is allocated instep1718.
• After the call setup, the MS1221 (MS₁) and the MS1231 (MS₂) request and get a bandwidth for the data communications. The MS1221 (MS₁) transmits data packets to the RS1220 (RS₁) using the allocated bandwidth instep1720. After receiving the data packets, the RS1220 (RS₁) decodes the corresponding packets and checks a destination MAC address instep1722. When the destination MAC address is a MAC address of the MS1231 (MS₂) in the coverage of the neighbor RS1230 (RS₂), the RS1220 (RS₁) relays the corresponding data packets directly to the RS1230 (RS₂) instep1724, not to the BS1200 (BS₁). For doing so, the RS1220 (RS₁) should know MAC addresses of MSs belonging to the neighbor RSs. To this end, a routing table is required. Information in the routing table includes field values relating to neighbor RS ID, MAC address of MS belonging to the corresponding RS, and so forth.
• After the call termination between the MS1221 (MS₁) and the MS1231 (MS₂), when the MS1221 (MS₁) sends a call termination message to the RS1220 (RS₁) instep1728, the RS1220 (RS₁) transmits call termination information/charging information to the BS1200 (BS₁) instep1730. In various implementations, when the MS1231 (MS₂) sends a call termination message to the RS1230 (RS₂) instep1732, the RS1230 (RS₂) transmits call termination information/charging information to the BS1210 (BS₂) instep1734. Next, the BS1200 (BS₁) or the BS1210 (BS₂) sends a call_termination_info_ack message to the RS1220 (RS₁) or the RS1230 (RS₂) (in steps not shown inFIG. 17).
• FIG. 18 is a block diagram of an RS for efficiently using radio resources in the communication scenario between the MSs in the neighbor cells according to an exemplary embodiment of the present invention.
• The RS ofFIG. 18 includes areceiver1800, acontroller1802, atransmitter1804, a receivingterminal checker1806, aMAC address checker1808, and acall setup unit1810.
• Thereceiver1800 converts a radio frequency (RF) signal received via an antenna to a baseband analog signal, demodulates and decodes the baseband analog signal according to a preset modulation level (modulation and coding scheme (MCS) level), and outputs the decoded signal to thecontroller1802.
• Thecontroller1802 processes the information output from thereceiver1800 and provides the result to thetransmitter1804. In addition, thecontroller1802 receives location information of the receiving terminal from the receivingterminal checker1802 and controls the call setup in relation with the receiving terminal.
• Thetransmitter1804 encodes and modulates the data according to the preset modulation level (MCS level). Next, thetransmitter1804 converts the modulated signal to an RF signal and transmits the RF signal over the antenna.
• When the call setup request is received from the sending terminal, the receivingterminal checker1806 locates the receiving terminal in relation with the sending terminal. How to locate the terminal departs from the scope of the invention.
• TheMAC address checker1808 can determine whether to relay data to the BS or to directly transmit to the neighbor RS or the receiving terminal, by checking the MAC address of the packet data of the sending terminal.
• In the call setup, thecall setup unit1810 generates the call setup request message and the call setup response message and exchanges the messages with the corresponding MS or BS.
• FIG. 19 is a block diagram of a BS for efficiently using radio resources in the communication scenario between the MSs in the neighbor cells according to an exemplary embodiment of the present invention.
• The BS ofFIG. 19 includes areceiver1900, acontroller1902, atransmitter1904, aresource allocator1906, and acall controller1908.
• Thereceiver1900 and thetransmitter1904 function substantially the same as inFIG. 18 and thus are not further described.
• When the sending terminal and the receiving terminal are traveling in the same RS service coverage, thecontroller1902 receives the message including the call setup information and the authentication/charging information from the RS and exchanges the call setup control information with the RS. When the sending terminal and the receiving terminal are traveling in the first RS service coverage and the second RS service coverage within the same cell, theresource allocator1906 allocates the CID for the connection between the first RS and the second RS. Thecall controller1908 transmits the call setup information of the sending terminal and the receiving terminal to the corresponding BS.
• As set forth above, in the wireless communication system based on the RS, the efficient utilization of the radio resources can save the resources and reduce the data transmission delay.
• Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.

Claims (20)

1. An operating method of a relay station (RS) for using radio resources in a wireless communication system based on the relay station, the method comprising:

setting a call with a sending terminal;

checking whether a receiving terminal of the sending terminal exists in the same RS cell, in a different RS cell of the same base station (BS) cell, or in a different cell of a neighbor base station; and

checking a destination address of a data and relaying the data to the receiving terminal according to a result of the checking.

2. The operating method ofclaim 1, further comprising:

transmitting an information relating to the call setup to a serving base station,

wherein a transport connection identifier (CID) is not allocated for a connection to the serving base station and a notification of the call setup is performed.

3. The operating method ofclaim 1, wherein, when the receiving terminal exists in the same RS cell, no radio resource for a connection to the serving base station is allocated and the data of the sending terminal is relayed directly to the receiving terminal.

4. The operating method ofclaim 1, wherein, when the receiving terminal exists in a different RS cell of the same BS cell, no radio resource is allocated for a connection to the serving base station, a resource for the connection between relay stations is allocated from the serving base station, and the data of the sending terminal is relayed to the receiving terminal through the connection between the relay stations.

5. The operating method ofclaim 1, wherein, when the receiving terminal exists in a neighbor cell of a different base station, no radio resource for a connection to the serving base station is allocated, a resource for the connection between relay stations is allocated from the serving base station, and the data of the sending terminal is relayed to the receiving terminal through the connection between the relay stations.

6. The operating method ofclaim 5, wherein a resource zone for the connection between the relay stations reuses an unused resource zone for the connection between the base station and the relay station.

7. The operating method ofclaim 1, further comprising:

when receiving a call termination message from the sending terminal or the receiving terminal, transmitting a call termination information to the corresponding base station.

8. An operating method of a base station (BS) for efficiently using radio resources in a wireless communication system based on a relay station (RS), the method comprising:

receiving a call setup information from a relay station; and

allocating a resource for a connection between relay stations.

9. The operating method ofclaim 8, wherein a resource zone for the connection between the relay stations reuses an unused resource zone for the connection between the base station and the relay station.

10. The operating method ofclaim 8, wherein the resource allocating for the connection between the relay stations is performed when a sending terminal and a receiving terminal exists in different RS cells of the same BS cell, or in neighbor cells of different base stations.

11. An apparatus for a relay station (RS) for using radio resources in a wireless communication system based on the relay station, comprising:

a call setup unit for setting a call with a sending terminal;

a receiving terminal checker for checking whether a receiving terminal of the sending terminal exists in the same RS cell, in a different RS cell of the same base station (BS) cell, or in a different cell of a neighbor base station; and

a controller for checking a destination address of a data and relaying the data to the receiving terminal according to a result of the checking.

12. The apparatus ofclaim 11, further comprising:

a transmitter for transmitting an information relating to the call setup to a serving base station,

wherein a transport connection identifier (CID) is not allocated for a connection to the serving base station and a notification of the call setup is performed.

13. The apparatus ofclaim 11, wherein, when the receiving terminal exists in the same RS cell, no radio resource for a connection to the serving base station is allocated and the data of the sending terminal is relayed directly to the receiving terminal.

14. The apparatus ofclaim 11, wherein, when the receiving terminal exists in a different RS cell of the same BS cell, no radio resource is allocated for a connection to the serving base station, a resource for the connection between relay stations is allocated from the serving base station, and the data of the sending terminal is relayed to the receiving terminal through the connection between the relay stations.

15. The apparatus ofclaim 11, wherein, when the receiving terminal exists in a neighbor cell of a different base station, no radio resource for a connection to the serving base station is allocated, a resource for the connection between relay stations is allocated from the serving base station, and the data of the sending terminal is relayed to the receiving terminal through the connection between the relay stations.

16. The apparatus ofclaim 15, wherein a resource zone for the connection between the relay stations reuses an unused resource zone for the connection between the base station and the relay station.

17. The apparatus ofclaim 11, wherein the call setter, when receiving a call termination message from the sending terminal or the receiving terminal, transmits a call termination information to the corresponding base station.

18. An apparatus for a base station (BS) for efficiently using radio resources in a wireless communication system based on a relay station (RS), comprising:

a controller for receiving a call setup information from a relay station; and

a resource allocator for allocating a resource for a connection between relay stations.

19. The apparatus ofclaim 18, wherein a resource zone for the connection between the relay stations reuses an unused resource zone for the connection between the base station and the relay station.

20. The apparatus ofclaim 18, wherein the resource allocator allocates the resource when a sending terminal and a receiving terminal exists in different RS cells of the same BS cell, or in neighbor cells of different base stations.

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